why does Mathews rate their IBO with " up to 343 fps"? other manufacturers simply just list the speed under IBO. Is there a difference ? is there some meaning to that or Mathews just wanted to give some variance to their IBO. meaning all bows may or may not hit that rating. idk I was just curious.

As far as Mathews goes, I believe the “up to ###” comment is attributable to certain bows having more than one let-off module option. A lower let-off mod is going to be faster than a high let-off module (i.e. 75% vs. 85%).